一种新型水下电场传感器研制

The requirements of marine security need fast and efficient detection and recognition of underwater target. As an effective technology, underwater electric field detection is currently under great attention. Since non-polarizable electrode has large electrochemical noise which is introduced by the seawater salinity and temperature, we intend to design a new type of underwater electric field sensor with chemical inertness. The main contents include: (1) To study the material of the underwater electric field sensor and surface treatment method, which effectively increase the coupling efficiency between the sensor and the electric field to be measured; (2) To study the underwater electric field sensor electrode and complementary detection circuit noise suppression methods, which improve the ability of underwater weak target detection; (3) To explore the test and calibration method of underwater electric field sensor. The Electric field sensor developed in future measure electric field in inducting way, will have better noise performance and stability than the existing non polarizable electrode.

海洋安全防卫要求快速、高效地检测和识别水下目标，而水下电场探测作为一种有效的技术手段目前正受到极大重视。 针对目前水下电场探测采用的不极化电极存在电化学噪声较大、受海水盐度和温度影响较大等不足，本课题拟研制一种新型具有化学惰性的电容性水下电场传感器。主要内容包括：（1）研究水下电容性电场传感器材料及其表面处理方法，有效提高传感器与待测电场之间的耦合效率；（2）研究水下电容性电场传感器电极和配套检测电路的噪声抑制方法，以提高对水下弱目标的探测能力；（3）研究水下电容性电场传感器测试与标定方法。研制成功的电场传感器将通过感应方式测量水下电场，具备比现有不极化电极更低的噪声性能和更好的稳定性。

本课题研究了水下电容性电场传感器的测量原理，并建立测量模型；根据电容性电场传感器对测量的电容要求和水下的应用环境对电极的材料进行仿真设计；研究了水下电容性电极材料的表面处理工艺，对电容性电极自身的噪声性能进行整体优化设计，完成了电容性电场传感器探头的研制目标。课题研制了基于斩波放大技术的低噪声检测电路，并对检测电路主要技术指标进行了测试。测试结果表明本课题所研制的钽电极探头噪声水平为0.7nV/sqrt(Hz)@1Hz；低噪声放大电路噪声水平为0.6nV/sqrt(Hz)@1Hz；电容性电场传感器整体噪声水平优于1nV/sqrt(Hz)@1Hz。课题还开展了水下电容性电场传感器标定方法的研究和部分关键模块的水下现场试验验证工作，为未来进一步开展全面的现场应用奠定了基础。